This invention relates to the art of borohydrides, more specifically to cyanoborohydrides and processes for their preparation.
The preparation of lithium, sodium and quaternary ammonium cyanoborohydrides by reaction of anhydrous HCN with the appropriate borohydride salt is taught by U.S. Pat. No. 3,667,923. The preparation of potassium cyanoborohydride in analogous fashion is taught by U.S. Pat. No. 3,697,232. A detailed study of sodium cyanoborohydride preparation is given in Inorganic Chemistry, Vol. 9, page 2146 (1970). Copies of the patents and of the publication accompany this application for the examiner's convenience.
The present invention provides synthetic routes for the preparation of cyanoborohydrides in good yield, and in high purity with improved storage stability while avoiding the presence of HCN either as a reactant or a by-product of the reaction.